AaronP, as a shareholder, you should care what a company does. Take this hyopthetical situation.
Say you own stock in Company A. Then one night, Company A decides to run a special TV show. The screen will be split, on the right side are ads for Company A's newest products and a number to call to order some. On the left side is a man killing puppies for every minute that goes by and they don't get 10 orders. It may generate orders, and it may boost earnings, but if enough shareholders see it and think it's terrible, they may sell their stock because they don't want to be known as a "Company A shareholder" And the price plummets.
It's a drastic case, yes, but it shows why you should pay attention to what companies you invest in do...if they make boneheaded decisions sooner or later profits are going to slip.
Besides, this fad will wear off eventually. Remember No Fear anyone?